For years, WAVmaker has been the undisputed leader in MIDI to WAV rendering.

Unlike sound cards and soft synths constrained by the requirements of real time
operation within a limited memory and CPU footprint, WAVmaker can turn MIDI files
of virtually unlimited polyphony and complexity into CD-quality WAVs with perfect
timing precision, using fully editable instrument patches, multiple, programmable
effect chains and samples of virtually unlimited size, without any of the noise
and distortion introduced by conventional recording.

The WAVs produced by WAVmaker are ready to be burnt on CD, included in applications,
uploaded to the web or processed further (e.g. mixed with vocals).